An interesting essay by Richard Carrier in Free Inquiry. The opening para reads:
What is naturalism? As a worldview distinct from any form of "supernaturalism," "naturalism" is the belief that nature is (probably) all there is, and nothing supernatural exists. Of course, the word naturalism can be used in other ways. In the art world, it means one thing; as a special term in epistemology, it means something else; and so on. But as a worldview, as a comprehensive picture of the nature and content of existence, naturalism is the converse of supernaturalism. What does that mean? Attempts to distinguish the "natural" from the "supernatural" often fail on basic requirements of coherence and utility. I predict that all successful attempts will reduce to this: naturalism is the view that everything mental is fundamentally nonmental. That sounds bizarre and unexpected, but it appears to be correct.